Shares in the Norwalk, Conn.-based online travel booker were up 6.3% at $630.60 after hours, which represents the highest price since July 1999. During regular trade Monday, the stock hit its highest point since March 2000.

However, executives noted the Priceline's trademark "Name Your Own Price" business was hurt in U.S. hotels by competitors' discount strategies and in U.S. air tickets by carriers' capacity cuts. They also said weak southern European economies were slowing business growth and increasing cancellations there.

The company--operator of its namesake website as well as Booking.com, Agoda.com and rentalcars.com--spurred investors with its forecast-beating revenue and earnings per share growth, as well as a stonger-than-expected EPS projection for the current quarter.

Priceline forecast earnings of $3.80 and $3.90 a share on revenue growth of 22% to 27% in the first quarter. Analysts surveyed by Thomson Reuters expected profit of $3.72 a share on revenue of growth of 25%.

Bookings exceeded company targets, too. In the latest period, gross bookings--the value of all travel services bought online--were up 52%, above the 44% top end of guidance. International bookings were up 66% versus an outlook topping out at 55% growth, while domestic bookings were up 16% versus a 13% forecast.

The international side has driven much of the company's booking growth in the last couple years, though growth rates have been decelerating because of the business's larger scale and more frequent tough comparisons. The company forecast deceleration in bookings for the first quarter.

However, while the company had expected international hotel room nights to decelerate over the fourth quarter, they actually accelerated, according to Chief Financial Officer Daniel J. Finnegan on a conference call with analysts.

Executives said they don't currently foresee any large technology platforms rebuilds like those that have been compressing profitability at rivals Expedia and Orbitz. The bottom lines at those rivals have struggled in 2011 because of the tech investments, especially compared with the soaring earnings of Priceline, but both have said the technology updates are driving stronger business as they're implemented.

Monday, Priceline posted a profit of $225.7 million, or $4.41 a share, up from $135.7 million, or $2.66 a share, a year earlier. Excluding stock-based compensation costs, earnings rose to $5.37 a share from $3.40.

Revenue climbed 35% to $990.8 million.

In November, the company's forecast profit of $4.90 and $5 a share on a revenue increase of 27% to 32%, below analysts' expectations at the time.